%%%-------------------------------------------------------------------
%%% @author Viktor Green <viktor@localhost>
%%% @copyright (C) 2011, Viktor Green
%%% @doc
%%% Gen server to keep things that are needed by the whole application
%%% and doesn't change.
%%% @end
%%% Created : 15 Dec 2011 by Viktor Green <viktor@localhost>
%%%-------------------------------------------------------------------
-module(singleton_storage).

-behaviour(gen_server).

%% API
-export([start_link/2, get_peerid/0, get_port/0]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
	 terminate/2, code_change/3]).

-define(SERVER, ?MODULE). 

-record(state, {peerid :: string()
	       ,port :: 0..65535}).

%%%===================================================================
%%% API
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @end
%%--------------------------------------------------------------------
-spec start_link(PeerID :: string(), Port :: 0..65535) ->
			{ok, Pid :: pid()} |
			ignore |
			{error, Error :: term()}.
start_link(PeerID, Port) ->
    gen_server:start_link({local, ?SERVER}, ?MODULE, [PeerID, Port], []).


%%--------------------------------------------------------------------
%% @doc
%% Get the PeerID
%% @end
%%--------------------------------------------------------------------
-spec get_peerid() -> PeerID :: string().
get_peerid() ->
    gen_server:call(?SERVER, get_peerid).

%%--------------------------------------------------------------------
%% @doc
%% Get the port
%% @end
%%--------------------------------------------------------------------
-spec get_port() -> Port :: 0..65535.
get_port() ->
    gen_server:call(?SERVER, get_port).

%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initializes the server
%%
%% @spec init(Args) -> {ok, State} |
%%                     {ok, State, Timeout} |
%%                     ignore |
%%                     {stop, Reason}
%% @end
%%--------------------------------------------------------------------
init([PeerID, Port]) ->
    {ok, #state{peerid = PeerID, port = Port}}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @spec handle_call(Request, From, State) ->
%%                                   {reply, Reply, State} |
%%                                   {reply, Reply, State, Timeout} |
%%                                   {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, Reply, State} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_call(get_peerid, _From, #state{peerid = PeerID} = State) ->
    {reply, PeerID, State};
handle_call(get_port, _From, #state{port = Port} = State) ->
    {reply, Port, State};
handle_call(_Request, _From, State) ->
    Reply = ok,
    {reply, Reply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @spec handle_cast(Msg, State) -> {noreply, State} |
%%                                  {noreply, State, Timeout} |
%%                                  {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_cast(_Msg, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, State) -> {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
    ok.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%%%===================================================================
%%% Internal functions
%%%===================================================================
